In recent years, an organic EL (Electro Luminescence) display device has been receiving attention as a thin, lightweight, fast response display device. The organic EL display device includes a plurality of pixel circuits arranged two-dimensionally. Each pixel circuit of the organic EL display device includes an organic EL element and a drive transistor. The drive transistor is provided in series with the organic EL element, and controls an amount of current flowing through the organic EL element (hereinafter, referred to as drive current). The organic EL element emits light at a luminance determined according to the amount of drive current.
In the organic EL display device, variations occur in the characteristics (threshold voltage and mobility) of the drive transistors. If variations occur in the characteristics of the drive transistors, then variations occur in the amounts of drive current and accordingly luminance nonuniformity occurs on a display screen. Hence, in order for the organic EL display device to perform high image quality display by suppressing luminance nonuniformity on the display screen, it is necessary to compensate for variations in the characteristics of the drive transistors.
Various types of organic EL display devices that compensate for variations in the characteristics of the drive transistors are known conventionally. For example, Patent Document 1 describes an organic EL display device that reads out a drive current externally via a power supply line, updates a correction gain and a correction offset based on a measured amount of the drive current, and corrects a video signal using the correction gain and the correction offset. Patent Document 2 describes an organic EL display device that reads out a drive current externally via a data line, updates a threshold voltage of a drive transistor based on a result of comparison between a measured amount of the drive current and a target amount, and corrects a video signal using the threshold voltage.
Apart from this, as a low power consumption display device, there is known a display device that performs pause driving (also called intermittent driving or low-frequency driving). The pause driving is a driving method in which, when the same image is continuously displayed, frame periods are classified as a drive period and a pause period, and a drive circuit operates during the drive period and the operation of the drive circuit is stopped during the pause period. The pause driving can be applied when transistors in a pixel circuit have an excellent off-leakage characteristic (small off-leakage current). A display device that performs the pause driving is described in, for example, Patent Document 3.